Look my INTENT is to boot multiple different ARM64 O/S from different partitions on a 1 terrabyte USB sata SSD disk for the Raspberry Pi 4B /8GB computer.
https://blog.manjaro.org/february-2023-in-manjaro-arm/ Manjaro ARM RK3399 fixes to U-BOOT 2021.10 in manjaro repositories.
Manjaro.org download area select ARM.
POP!_OS Download area. Select ARM for Raspberry Pi 4.
So I am thinking maybe their ARM64 efibootmgr and efivar programs are better than the 'boot 0000' of FreeBSD efibootmgr program. Maybe one could use their source to work with FreeBSD ARM64 to make a multi-partition boot order selection. Your thoughts.
Second point,) I am at the initial debug capability of write an image to a USB flash drive, plug it in to Raspberry Pi 4B, turn on the power, Is it working? or is it broke? yes broke, what happened what printed on screen. Some how relate that to lines of code somewhere.
What ARM64 supporting tools do you use to debug ARM64 hardware when the code stops running. Visibility? I have ordered the Tigard Board to obtain ARM64 JTAG capability and 3.3V TTL serial port connection. I have 3.3V TTL serial port connection now today with the Black Magic Probe (BMP) device. So, yes, I can see the print messages during boot up. You presently use a FTDI USB to serial TTL device connection at 115200 serial baud.
What techniques do you use for debugging a broken boot or broken kernel boot up?
Third point.) After FreeBSD kernel is booted up and running. You can type command s date , ls, pwd , whoami and others. Do you have any URLs recommend to read up on using DDB for ARM64 kernel debugging. Like for debugging a WIFI device driver code for the 43455 or 43456 wifi chip?
Tigard Board JTAG for ARM64
https://www.crowdsupply.com/search?q=tigard
Bit Magic Basic Logic Analyzer 8 bits
https://1bitsquared.com/products/bitmagic-basic Works with Tigard board.
1 BIT SQUARED Black Magic Probe BMP debug for ARM32 bit M0 core
https://1bitsquared.com/products/black-magic-probe
Any extra devices you connect to the hardware to help you debug better, with a little more visibility? Glowing leds, logic analyzer, extra serial ports ( I could turn on serial port UART3 on the raspberry pi 4b.)
Fred Finster Ghostbsd-Arm64.blogspot.com my ARM64 debugging posts to help me remember what I did to get here with having FreeBSD 14.0-CURRENT now 15.0-CURRENT running on the Raspberry Pi 4B hardware. Wow, I did watch a number of Raspberry Pi 5
https://youtube.com on this new hardware release from
https://raspberrypi.com
FreeBSD subtopic Forums Raspberry Pi FreeBSD install with patching VCHIQ for HDMI TV Sound